Hi
After a few years of analog operation, my Cruzbike T50 has received a digital upgrade. Not aimed at a better performance or the like, rather as one platform to measure physical effects related to bicycling. A small DAQ system based on a microcomputer is now capable of recording and processing signals from various sensors attached to the vehicle.
A simple application is that as a fast-sampling speedometer, employing just the spoke magnet(s) for the timing signal. Fig. 1 ** shows the very first measurement. [Location: quiet neighborhood street in Northern Germany. After sunset, to be able to read the display]. The T50 was brought up to speed and then let go (Cruzing mode). Velocity decreases with time . Air, tire and hub resistances effect the deceleration a, which can be extracted from v(t), a= dv/dt in quasi real time. Translation into forces is done by multiplying with the mass (incl. inertial moments of the wheels). F=m*a.
Air and rolling resistances can in principle be disentangled by their v-dependence, or, as many other effects determined by reference measurements (including relevant system and environmental parameters, such as wind speed, slope, tire temperature, variations of the gravitational constant...).
Cruzing yields the energy resp. power taken out by the driving resistances; it cannot address drive train efficiency or driver ergonomics.
It might be also more interesting for the high-speed community.
Caveats: I'm not sure 1) whether this qualifies for 'Innovations' at all and 2) if and how I can include figures in a post. **
Bear with me, if you will.
Greetings
After a few years of analog operation, my Cruzbike T50 has received a digital upgrade. Not aimed at a better performance or the like, rather as one platform to measure physical effects related to bicycling. A small DAQ system based on a microcomputer is now capable of recording and processing signals from various sensors attached to the vehicle.
A simple application is that as a fast-sampling speedometer, employing just the spoke magnet(s) for the timing signal. Fig. 1 ** shows the very first measurement. [Location: quiet neighborhood street in Northern Germany. After sunset, to be able to read the display]. The T50 was brought up to speed and then let go (Cruzing mode). Velocity decreases with time . Air, tire and hub resistances effect the deceleration a, which can be extracted from v(t), a= dv/dt in quasi real time. Translation into forces is done by multiplying with the mass (incl. inertial moments of the wheels). F=m*a.
Air and rolling resistances can in principle be disentangled by their v-dependence, or, as many other effects determined by reference measurements (including relevant system and environmental parameters, such as wind speed, slope, tire temperature, variations of the gravitational constant...).
Cruzing yields the energy resp. power taken out by the driving resistances; it cannot address drive train efficiency or driver ergonomics.
It might be also more interesting for the high-speed community.
Caveats: I'm not sure 1) whether this qualifies for 'Innovations' at all and 2) if and how I can include figures in a post. **
Bear with me, if you will.
Greetings
